Automatic constant downstream level gate

ABSTRACT

The control gate herein embodies a sector float immersed in a container which is in communication with the tailrace through an opening formed between the lower end of the downstream wall of the container and its base which projects downstream beyond such opening to shelter the latter from the tailrace current.

lUniinnl initon nlinni Allnirnnnlrn E951? 222 ll W2 [54] AUTMATHC@QNEBTANT FOREIGN PATENTS OR APPLICATIONS DUWNWREAM LEVEL GATE 460,7191950 Italy ..61/25 [72] Inventor: Philippe Alexandre, La Trouche, France[73] Assignee: Sociene GIEIIEI'EIEIE do Constructions Elec- 33 523:emecmmms (Mmmmx Greno- Primary ExaminerJacob Shapiro Attorney-Sylvester.I Liddy, John J. Han, Joe E. Daniels and [22] Filed: Dec. 29, 1970Charles E. Baxley [21] Appl. No: 102,286

[30] Foreign Anplicaiion Priority Data [57] ABQTRAQT Jan. 5, 1970 France..7000464 The control gate herein embodies a Sector fl immersed in acontainer which is in communication with the tailrace through [52] ILLS.Ci ..61/22, 61/25 an Opening formed between the lower end of thedownstream [51] m 7/52 wall of the container and its base which projectsdownstream [58] Field! oil Search ..61/22, 23, 24, 25, 26, 18 beyondsuch Opening to Shelter the latter from the taflracg [56] ReIerencescared current UNITED STATES PATENTS 2,168,117 8/1939 Dane] ..6l/25 2Claims, 2 Drawing Figures PATENTEDFEB22 I972 FIG.

FIG. 2

IN VEN TOR. Pl-l/L IPPE ALEXA AID/8f BY AUTOMATIC CONSTANT DUWNSTREAMLlEVlElL GATE This invention relates to gates for automaticallycontrolling the flow of water in canals, streams, etc., and moreparticularly to control gates designed to maintain automatically aconstant water level downstream therefrom.

Gates of the type with which this invention is concerned are usually ofunit construction and mounted for pivotal movement above a main pivot.The unit is provided with an up stream gate apron centered on its mainpivot, and a downstream float for controlling the operations of the gatein maintaining the downstream water level.

The primary purpose of the instant invention is to provide an improvedmeans for dampening the oscillations of the gate during the lattersoperation ad for sheltering the downstream float thereof from theeffects of the tailrace and from foreign bodies carried by the tailrace.

Other objects of the invention, as well as the features and advantagesthereof will appear from a consideration of the following descriptionread in connection with the accompanying drawings in which FIG. l is aschematic view of an automatic constant downstream level gate having itsdownstream float encased in a container embodying the invention; and

W6. 2 is a partial view of the bottom end of the container on anenlarged scale.

The automatic gate unit, which is shown in its fully opened position inFIG. 11 of the drawings, comprises a frame arm 3 which extends upstreamfrom a fulcrum 2 about which the whole of the gate pivots and on theouter upstream end of which is mounted a sector-shaped apron 1 radiallydisposed to the pivotal axis 2. The unit also includes a hollow sectorfloat 4 which is centered on the pivotal axis 2 so as to be in opposingtorque to the apron i.

As indicated in FIG. 1, the gate is mounted in a canal 12 so that theapron ll coacts with a sill lll formed in such canal to control the flowof water so that there is maintained in the tailrace 13 downstream ofthe gate a constant level N which is the elevation of the main pivot 2of the gate. The gate is balanced by a weight 7 adjustably positioned ona post 8 carried by the frame arm 3 so that when the downstream waterlevel N is at the elevation of the gate pivotal axis 2 and the gate iscompletely closed, the torque generated by the hydraulic thrust on thefloat 4 will balance the torque generated by the weight of the gate. Solong as the condition is maintained the gate will remain closed. W hen,however, the downstream water level N of the tailrace falls, the gatewill automatically, immediately open to permit a larger dischargetherethrough sufficient to restore the water level of the tailrace tothe level N.

lln order to dampen the oscillations of the gate during its operationand to isolate the float t from disturbances in the surface of thetailrace 113 at the level N, the float 4 is immersed in a fixedcontainer which projects above the tailrace level N and which iscarefully matched in configuration to that of the float so that thechamber defined thereby is only slightly greater in volume than thevolume displaced by the float. The container 5 is provided with atransverse slot or opening 6 affording communication between the bottomof the chamber therein and the tailrace so that the water can flow intothe container chamber and be discharged therefrom during the oscillatingmovements of the float 4 in the operations of the gate. It will be notedin the drawings that the opening 6 is formed by a space between thelower end of the downstream wall of the container and the base or bottomwall 9 of such container. The base 9 of the container 5 has an extension10 projecting downstream beyond the opening 6 in downwardly inclinedrelation to the current flow. This extension 10 shelters the slot 6 fromthe current F produced by the apron 1 and the sill 11. This result isaccomplished because the downwardly inclined extension It) creates inthe tailrace a zone 15 of relative negative pressure in front of theopening 6. This depressurizing of the zone 15 in front of the openingwhich may be termed a suction effect, causes the level N in the floatcontainer or tank 5 to be slightly lower than the level N of thetailrace, improves the dampening of the float 43 by the container 5, andimproves the stability of the gate for equal ef fective adjustments ofthe decrement of the gage (the term decrement being here used todesignate that variation in the downstream or tailrace level whichcauses the gate to move over the full range of travel for which it wasdesigned and ad justed). The thus created depressurized zone has beenfound to provide a further advantage in that it prevents the movement offoreign bodies that may be carried along by the current through theopening 6 and consequently the entry of such bodies into the container5.

Iclaim:

1. An automatic control gate for maintaining a constant downstream waterlevel comprising a frame, means on said frame for mounting said gate forpivotal movement about an axis located at the level at which such waterlevel is to be maintained, a sector-shaped gate apron radially disposedto said pivotal means mounted on the upstream end of said frame, asector float on said frame centered on said pivotal means and extendingdownstream therefrom, and a container fixed with relation to said sectorfloat and adapted to be submerged in the tailrace water downstream fromsaid pivotal means, said fixed container having an upper open endreceiving said sector float and projecting above the downstream waterlevel, said fixed container having a contour substantially matching thatof said float, having an opening bringing the interior of said containerinto communication with the water in said tailrace, and including meansassociated with said opening to produce a depressurized zone locatedadjacently in front of said opening and exteriorily of said container.

2. An automatic control gate as defined in claim l, in which saidopening is formed by a space between the lower end of the downstreamwall of said fixed container and the bottom wall thereof, and in whichsaid associated means is constituted of an extension of said bottom wallprojecting downstream beyond said opening.

mun

1. An automatic control gate for maintaining a constant downstream waterlevel comprising a frame, means on said frame for mounting said gate forpivotal movement about an axis located at the level at which such waterlevel is to be maintained, a sector-shaped gate apron radially disposedto said pivotal means mounted on the upstream end of said frame, asector float on said frame centered on said pivotal means and extendingdownstream therefrom, and a container fixed with relation to said sectorfloat and adapted to be submerged in the tailrace water downstream fromsaid pivotal means, said fixed container having an upper open endreceiving said sector float and projecting above the downstream waterlevel, said fixed container having a contour substantially matching thatof said float, having an opening bringing the interior of said containerinto communication with the water in said tailrace, and including meansassociated with said opening to produce a depressurized zone locatedadjacently in front of said opening and exteriorily of said container.2. An automatic control gate as defined in claim 1, in which saidopening is formed by a space between the lower end of the downstreamwall of said fixed container and the bottom wall thereof, and in whichsaid associated means is constituted of an extension of said bottom wallprojecting downstream beyond said opening.